Abstract: IPG single-mode fiber laser was used to conduct laser scanning welding test for T2 copper, and the weld surface morphology, cross-section shape and microstructure of the samples under different welding speeds, welding times in single side welding and double-sided welding and other process parameters were compared and analyzed. The results show that the welding speed has a great influence on the appearance of laser welding of copper. When the welding speed is 10 mm/s, the fish-scale lines on the weld surface of the sample are uniform, fine and continuous, and the defects such as hump and splash are significantly reduced. The microstructure of the welded joints is mainly fine equiaxed grains in the weld zone and coarse columnar grains in the fusion zone. With the increase of welding speed, the equiaxed grain zone in the weld become narrower and the grains become finer. The weld width and weld depth of the single-side rewelding sample increase compared with those of the single-side single welding sample, but local thermal damage is easy to occur, and the grains in the weld area of the sample become coarser.When double-sided welding is used, the weld surface forming quality of the sample is poor, the fusion area at the bottom of the weld has pores, and the grains in the joint area are coarse.